How to create a texture for icicles
Final:



Node setup:



This is pretty simple setting, mixed Wave Texture with Noise and used as Bump for Glass.

Before this you have randomization for Z position per object to make icicles looks different from each other. They should be separated objects.

Mesh notes:

It's not part of the question, but I'll try to briefly describe how to use it with this add-on.

To get this working you need to have UV Map for icicles. 
I've used Cylindrical Projection on all of them.

After this I've separated icicles - P > By loose parts.

Another issue could be Smooth Shading. Check here for solution: Smooth cone with glossy or anisotropic texture gets dark spot or use Flat Shading.